IBM ThinkPad T21 Problem

[bronxnino]

Here's my situation.

I bought an IBM ThinkPad T21 2647 4AU from my company. They were selling them because they upgraded. Of course, they sold it "as is" and there is no support for them.

The IT department formats the HD so I had to install all of the software from scratch.

Before I installed Windows, I was able to turn the thing on with just battery power. Of course it was only DOS with the minimum programming necessary but, it turned on none the less. I was with a friend of mine who "knows" about computers when I installed windows. When the part of the install came up showing how the HD was divided, two partitions with about 5GBs on one and 15GBs on the other, my friend said to delete the partition so that I can have all 20GBs available. I did this.

It seemed to be going okay. I installed XP without any trouble and the laptop seemed to be working fine. Mind you, I did all this with the thing plugged in.

When it is plugged in, it works just fine. I'm using it to post this thread now.

However, the thing will not turn on at all when it's not plugged in. Sometimes, when it is plugged in, and I have to turn it off and turn it on again, it doesn't turn on. It does turn on again when it sits for awhile (plugged in).

When I have it plugged in and pull the power cord out, it will sometimes turn off and sometimes stay on and switch to battery power however, it will only stay on for about 15 minutes and then shut off.

I've already:

1) Tried about 4, fully charged, batteries
2) Removed the memory cards and tried it without and with, just one and one at a time
3) Removed and reset the HD.

Removing and resetting the HD actually worked the first time that I turned it on but, after I shut it down, it didn’t turn on with just battery power again. Because it did work for this brief period of time, I’m lead to believe that I’m heading in the right direction but, because I don’t know enough about laptops, it’s not clicking.

Can anyone out there help?