Serious laptop problem!

I have Thinkpad A20P with number of problems(or maybe one big):

-sometimes dont want to power up, all power lights flash like normal but thats it
-sometimes freezes on XP boot up
-i have seen perhaps all BSOD messages form Windy (0x0000000a, 0x00000050, 0x000000e3, 0x00000008)
-when i disconnect battery and run it from AC adapter, its is veeery unstable
-sometimes when i knock him freezes
-after POST cpu fan stop (i dont know is this normal or not)
-sometimes when i connect usb stick it freezes

by the way this was review of an very cool !?! deal (100 bucks).
My first impression when i bought it, was that battery is old (which is, 40min of juice) and i can live with it. But problem like this i think dont comes from just old battery. I tried almost everything : swap ram position from one to another slot, reconnect battery and the adapter, upgrade and downgrade bios, disconnect and reconnect all cards and drives, but nothing fixed the problem, altought some temporarily fixed the problem and i can use the laptop normally.
If anyone has experienced problem like this please help me .

 

I guess that is what happens with a $100 machine. Alright, it seems to be a hardware issue if you've changed the bios several times as well.
Have you done a clean install of Windows and reformated the Hard Drive?

When you bump it, it freezes, seems like it is a hard ware issue. Just old components that are fragile. Connecting USB makes it freeze as well, your motherboard is almost done.

 

If you have any warranty or guarentee on the machine I would excersise it.

 

I dont have warranty or guarantee (what you want for 100$), but im willing to exercise any solution to that problem(s), no mather how hard it is, ill do it just for sake of doing it.
By the way there are problems (situations) which are not so catastrophic, like: halting fan and running on AC adapter to which can answer anyone who used this or similar thinkpad. If that is cleared to me i have smaller bunch of problems to work (which i think are directly connect to RAM and slot for RAM and junky battery). I have reformatted the hard, and moved from win2000 to XP-which is much stable. 1 from 10 times when i stick usb stick freezes, if there was motherboard problem it would freeze all the time?.

 

Maybe it is as simple as defective RAM, although your symptoms suggest additional hardware problems. I suggest that you get the free Ultimate Boot CD and check your notebook's RAM and other components.

 

Finally success ! , ITS the Ram, but its sort of a slot problem, - the ram didnt sit well in the slot and after some improvised lifting (with cotton ) of the ram board, success (when you install the ram in the slot you must Push it DOWN, which in these case ITS a bit of a problem). System works perfectly , but im still puzzled with CPU fan action. And im interested in a battery repairing. If anyone have any kind of information about these two problems, im willing to listen (read ) very carefully.

 

The CPU fan is temp controlled. After POST the fan on my X21 and T60 turn off and then only turn on when they are needed.