I have installed 256mb SDRAM 133mhz -168pins on my 100mhz motherboard . Pentium III 700mhz processor.Compatability checked
It will not register on the system - I have been told to remove the battery and try again - still nothing - Can you help. I am told I need to flick some jumpers???
This is a TINY computer Q053

There are many posibilities.

It's possible one of the RAM ports is dead. Since RAM needs to be inserted in order, you can't just put it in a different slot. To test this, if you can get your hands on some RAM you know works and put it in the slot.

It also could be the RAM is bad. Test it by putting it in another computer.

A third possibility is your computer simply doesn't take unbuffered RAM. Search the Internet for your motherboard's chipset and see if it works.

Also, you could have put the SDRAM in a DDR slot, if your motherboard has any. You might want to check that.