I am having problems with my compaq presario 2100 and please i know ....not a great machine.. :) Anyway the computer just crashed the other day so i did some looking around at it. I have found that if you pull one of the sdram chips out the machine will run but if you put them both in the machine will do one of two things. Either fire up for two to three seconds and then shut off and continue the same thing untill you pull the battery out the other is the system appears to start up with hard drive running and everything but no screen display. Now i am running with just one 256 sdram which is great but i would like the other one in there too..... any thoughts out there???

sounds like bad ram, do any of the contacts look fried?

The best thing you can do with OEM machines like this is call up the manufacturer, tell them your problem, and if the product is still under warranty, they will fix it.

Since you took the side panel off however, you have probably voided said warranty.

www.memtest86.com

Download it, boot with a disk on it, run it for a few hours with both sticks installed. If you get errors with a particular stick, replace it.