Computer was restarting several times. We called tech support and they had us check memory. They said it was ALMOST out of memory and we ordered more memory. We are running Windows XP. We put memory into SLOTS as directed. Now when you push the on/off button on tower it stays amber, never turns green. A box shows on computer screen says self test, no signal. then another box comes on saying computer is in energy saving mode. The fan in the tower is not running.We have tried to get into SAFE mode but nothing including keyboard works. Do you have any suggestions?What are the SPECIFICS of the machine - make/model, RAM before and after the upgrade, where did you get the memory and what kind, etc. would be helpful and someone will be along shortly to help.Sorry didn't include that. It is a Gateway 700S PC, 256MB RDRAM PC 800 memory.  We bought computer in 2001. Gateway suggested another 256 MB (put in two 156 MB). My husband removed them and sent them back to Gateway for refund. Gateway said could be bad motherboard, power supply not working or bad battery. My husband bought new battery, STILL they same. He checked power supply, said nothing wrong. Have not had mother board checked, hoping nothing is wrong with it. Am not able to do anything on computer. Lights on keyboard do not work as well as no keys working. Mouse lights up but no pointer on screen. Put disk in CD/DVD trays. They do not work. Let me know if you need anymore info. Thanks.Either it is a bad or poorly connected power supply, or some sort of disastrous motherboard issue as a result of or causing a bad power supply.

I don't believe RAM was ever the issue. How was the power supply determined to be good?