What type of "weird" problem? Describe in detail. Nowadays CRT monitors have little value (not worth fixing), may as well get a LCD/LED monitor.

If that line stays in the same place all the time including during the BIOS POST screen then its likely a panel problem. How old is that monitor, and is it still under warranty?

Brand, model and size? Try tapping on the top frame area of that line, and see if it changes color or more lines appear. You can also try pressing slightly (not too hard) the top area where the line starts from, and see if there are changes...

Size? You can check the model number on the label at the back of the monitor...

Does it appear all the time, or just appears after some time? Usually for panel problems, have to replace whole panel. Other than that, have to know how to check for cracks or connection problems at the TCP (tape carrier package) on the panel. Do you know how to do that?

// Edit: See example below...

Whoah! That's monitor uses a PMVA panel (true 16.7 million colors) instead of the usual TN panel. Also its native resolution is actually 1680x1050 instead of the usual 1600x900 found on most 20" widescreen monitors nowadays. 

You have a few choices, really. First, just continue to use the monitor while ignoring that line. Second, get a new monitor and put aside that monitor as spare or sell it off as scrap. I could also take a look closely and see if I could apply the tape+padding trick though the chances are quite low for it to work since tapping, pressure and warming up on the panel did not alter the line in any way. Anyway, the tape carrier thingy is pretty delicate and further influence could make it worse (e.g. another line appears). That's why for this type of problem, usually whole panel has to be replaced although its not recommended as the price of that replacement panel alone (usually anywhere from at least RM200 and higher) can buy a brand new monitor (ie. usually only worth for monitors sizes 23" and above).

This one is usually the power supply section, usually badcaps. But the "pop" sounds could be from the backlight section (again possible badcaps). This one is usually easy to fix. If you want, the just ask/PM me...

I've used quite a number of monitors already, though mostly from Acer and BenQ ones, and a few Samsungs. My current one, BenQ FP222W has been running fine (already 5 years). Usually I tend to stick to known big/established brands, rather than going for less known ones like Envision, Proview, IIyama, Planar, VHO, etc. Hardware support is pretty important for LCD monitor.

As many has mentioned/recommended here, bigger than 20" would be Dell UltraSharp U2312HM...

No idea, but the symptoms described (in bold) are usually indicative of power supply problems (e.g having to switch off or disconnect before can switch on back again).

Short for "bad capacitors". In many power supplies, capacitors can determine the stability of the power being delivered. If capacitors go bad then will have random and intermittent problems.

AOC is actually an OEM for many monitor brands, though nowadays they decided to also compete in the market under their own brandname. The others like Acer, BenQ and Samsung are also OEMs to brands like Dell, HP, IBM, etc. Generally in terms of spare parts and replacements, brands like Acer, BenQ, Samsung and Dell are plentiful and easier to find since they are more common...

Nope, still white with no hint of yellowish at all. But its not as bright or as "whitish" as before though. At least it was not reddish (for your information, reddish is usually an indicator of failing CCFL). Mine uses AUO panel (opened up before) while I've seen other FP222W monitors with Chi Mei panels (and different layout internally). Talking about white, my ancient Acer AL1717 is truly paper white (talking about brand new paper color) despite its age. Even my other monitor, Acer H233H (with Samsung panel) cannot match the older Acer monitor when it comes to white.

Which IPS monitor will you choose next? Viewsonic or Dell?

just ordered from DELL, Ultrasharp U2312HM for RM589. my first IPS panel.

currently using Viewsonic VX2025WM. P-MVA panel.

oh dangg!!!! how less? my warranty is 3 years only. I thought DELL can only be purchased from DELL online/store.
the reason why I change monitor is due to tompok-tompok kuning on the screen. It is not a dead pixels. This VX are fav. among my friend, we can conclude that this VX is really has problem. After few months using it, the DVI will burnt.  but old story. no more production last 5 years.

The U2412M has a different aspect ratio thus more vertical pixels. To some this is very important. IIRC performance wise they are about the same.
Dell U2312HM - RM600~ ,23" IPS display with anti glare coating,has a stand that can swivel and tilt.
Dell S2340L - RM560~ ,23" glossy IPS display [makes text a bit sharper,and colors a bit punchier],slim bezels,ok stand
Viewsonic VX2370S -  RM550,23" IPS with anti glare coating,decent stand
Acer V246HYL - RM525 [Jayacom],24" IPS with anti glare coating.

Generally speaking the image quality between these monitors should be about the same,unless you get a unit with excessive backlight bleed or dead/stuck pixels etc etc. The glossy models should have punchier colors but be prepared for glare. Gaming wise, I can't really say. Personally I don't think they would be noticeably slower or less responsive compared to a TN panel monitor.

from your description.. it is better to get U2412M compare to the other that you mentioned?

Or which do you recommend?

Got warranty? Coz some is ARB unit.