Random 'beep' freezes.

Hello fellas,

3 year old pc, recently cleaned of all spyware no problems with it previously.
Last couple of weeks, if im running more than say two programs, theres a tendency (like once or twice a day now), when i try to select a window, the cursor moves but won't let me click anything. If i try to go down to the taskbar it just gets to the edge of the taskbar and the cursor turns into the one with the arrows on either end.

It normally gives me about 3/4 attempts at clicking on something and then beeps and at that point the cursor and machine just lock up. Unable to alt-ctrl-delete or even reboot on/off from the front of the tower. I'm forced to power down round the back and then reboot.

Hijack this isn't showing anything dodgy. Also, when I reboot, about 3 or 4 times ive had a blue screen and it says something about firefox profiles, cache, first allocation is not valid entry will be truncated. Says this about 10-15 times down the screen for different numbered entries. Im baffled.

 

Can you post your system specs?
Processor
HD
Memory
Video Card
Power Supply
Anti Virus
Firewall

 

Ok its a AMD Athlon XP 1800+, 1.54 ghz with 224 Ram.
samsung sv4002h 40 gb hdd, (10gb free)
128 ram memory

memory bus properties
bus type - ddr sdram
width - 64 bit
real clock 134 mhz (ddr)
effective clock - 269 mhz
bandwith 2150 mb/s

s3graphicsprosavage ddr - video
antivirus - avg free
firewall - windows standard

no idea on power supply - where would i find that. Its standard uk, although i do live in spain so i had to switch the plug on the cable. Ive lived here two years tho and its only in the last two weeks this has been happening really. Although it did hang in the hottst part of summer but i think that was heat. This time as I said, I still have mouse movement but without functionality of select, and it always gives me approx 6 presses before the beep and then complete freeze.

About 1/8 times I get the firefox message on restart.

 

Sorry its 256 Ram - why can't I edit the post?