T-21 shuts down or freezes

[jjmclean]

Got a T-21 that has been sitting for a while. Got it out the other day and tried to boot it up. Sometimes it will stop in the BIOS and sometimes it will open windows, no particular place. On occasion it has ran in windows a couple minutes but probably never over 5 max. Sometimes it goes black screen and again sometimes it will freeze up and the screen stays lit. The battery has gone bad I think because it shows 50% charge when you first start up and never goes above or below 50%. I've removed the battery and tried to boot but had the same results. Any suggestions to diagnose this problem?
Thanks for any help

[vanaya]

It doesn't sound like the usual ethernet card problem, but it is the easiest to remove and rule out. It does sound like and overheating problem, I would recommmend opening and doing complete cleaning. While you're in there evict all the dust bunnies!! Remove cpu, clean old thermal paste, and applying fresh coat.

[Masi_K]

But remember to NOT toss that "rubber" thingy away from between cpu and heatsink. That has to be there.