I received a 10-year-old computer from a friend who complains that it is running very very slow (slower than a tortoise!).

When I checkout the RAM, it has 2 x 128 MB DDR 133 RAMs installed, but only 96 MB is detected.
I've tested both the RAMs and they are OK.

Is it possible that the memory slots (DIMM?) on the motherboard that are defective?

Thanks.It's possible that either the RAM or the slot is faulty.
Is the RAM detected in the BIOS?
Try each slot with one stick of RAM, then the other.Is the ram of the same mfg? somtimes there is conflict .The two RAM are not from the same manufacturer, but they are working FINE in the past.

I've tested both the RAM :

1. one stick on each slot - error "long beep" and cannot BOOT (same with either stick and either slot)
2. replace both STICKS - OK, but BIOS still detected only 96 MB (either same manufacturer or not, and either slot) download MEMTEST and run the test You can find the site at majorgeeks.com under memoryI removed and RESEATED both the RAMs a few times, and it works now.
So I guess there must be some kind of contact problem with the socket/holder.

I've also tested both the RAMs with MemTest and no error was found.

Thanks.