Power Supply or? Help me findout

Hello,

Well it goes like this, for 2 years + my computer has been having problems from time to time and recently it just became more often.
My Pc config:
Athlon xp 3000+ (running @ 1.9ghz - underclocked it, else my windows wont boot anymore).
ATI Radeon 9800pro
Crucial XMS PC3200 DDR400 512mb x2 (dual channel)
A 550watt Power supply from an unknown company somewhere from asia
Harddrive 80GB Maxtor 7200RPM (windows is installed on this one)
Harddrive 250Gb of WD 7200RPM (connected to a raid controller on my PCI slot)
and other things that arent relevent I guess.

*
Anyway, I one day heard a click sound repeating, coming along with freezing screen every few seconds on windows, I checked it out and after I restarted, my HDD didnt get detected by the controller, and windows didnt show it anymore after I logged on.
I turned off the pc, connected and disconnected the power sourceof the Hdd and afterwards it detected it again, and everything was good as it seems.
This problem happens at least once a week nowdays.

And I also had one day few months ago a windows Freeze, and after I restarted, windows wouldnt boot anymore no matter what, my computer got froze everytime I tried to reinstall windows or do anykind of task that requires processing/memory, couldnt even install "very small linux" it froze also. I went inside my bios and tried to play with the Cpu speed, I set FSB to 200 and multi to 9.5x, so at the moment the CPU is underclocked @ 1.9Ghz, But this solved the problem, and windows once again booted after I reinstalled, with 1 problem afterwards: when I installed ATI drivers catalyst it wouldnt let me see any settings options or open it up, and when I open it I get an Error("CLI.EXE ERROR, The app failed to initilize properly(0xc0000135)." ), all my games works as before tho.

I read an article just today that some of the symptoms I had been expiriancing might be due to a sucky Power Supply so I decided to go into it and look abit, and I found this:
My LCD bay infront shows really low +5v volt temps 4.5v and below sometimes. I downloaded Motherboard Monitor 5 and it says Avg is 4.88V and in "Low Field" it shows 4.57v, "High" showes 5.03v. No idea whos more accurate then the other but the lcd always beeps the voltage is low, almost never above 4.7v on the lcd at least.

I dont really have another power supply to check it, but if it is the power supply I wanna buy a good one not sure which yet.
I would appriciate any suggestions about my problem, if anyone has an opinion about it, since I'm not sure if it is the PSU, I planned to switch my CPU,memory,mb, hdd, graphics card cause all the problems involved the following :S, yeah, a new pc almost, but if I have another choice...

Thanks In advance and sorry for the long post ;x

I'm planning on getting Thermaltake 470W atx 2.0v as a new PSU, since its a good one from what I read and price is within my range, getting this cuz I plan to move onto anthlon 64 sometime in the near future.

My mobo is Asus A7N8X deluxe rev2.0 btw.

I think you can fix that CLI.EXE error by installing the .net framework from microsoft.

I never had a HD die on me (knock wood), but I did have that MB at one time and I also had a PSU that had a crappy 5v rail. It caused a lot of random issues.

You said you were going to upgrade soon, so be sure your new PSU will be able to handle the new sys req.

I forgot to ask before (I was at work....not working obciously)

Did you determine which disk was making the clicking? Maybe try running just the windows disk with the other unplugged, then switch it around.

Chances of both disks being bad is slimmer.

Oh yah....and that CLI.exe error....of course remove the drivers then install .net then reinstall,...just wanted to be clear

Good Luck

Another update: my HDD just started clicking again right now few mins ago, I checked the volts of the +5v rail and it said 4.6v on Motherboard monitor 5 and 3.5v-4.3v on my lcd bay. After that my pc froze every sec and couldnt access my 250gb drive, and after restart, it didnt detect, I opened pc and reconnected some power cables and turned pc on and worked again.

Btw this started after I loaded a really heavy game - Lineage2 which uses tons of memory, CPU, HDD loadings and graphics performance.

wow i got 1 Maxtor DiamondMax IDE @ 5400RPM, 2 seagate barracudas ATA @ 7200RPM's for almost 5 years, no problems, im using all 3 to this day. how do u guys screw ur HDD's up?

I know, a lot of ppl assuming its a HDD problem, I think otherwise tho, specialy after I read the sticky thread about the PSU symptoms for failing PSU, and it said "Drives not being detected properly or at all on bootup or taking a long time to do so. Drives or devices failing to run reliably or 'dissapearing' from windows in a random fashion. Random lockups, crashes or spontaneous reboots. Usually more common while the system is under heavy use, but not allways. " which is exacly what I get, adding to that, that I have a no name - bad company PSU and volts are dropping like crazy when I load something, after I paid attention to it. So I wouldnt say it's the HDD right away, but I already ordered a new PSU and I should have it sometime this week and I shall see if the HDD keeps making this problem.

edit: and adding to that the fact that I had to underclock my cpu so it works, otherwise windows wont boot, and in the symptoms it says "Inability to overclock reliably despite repeated attempts. Underclocked systems at 100FSb run ok, but fail to boot or run stabily at a normal 133FSB. ".