A few months ago the RAM in my computer was upgraded from 64 MB to 192MB. About a month after the upgrade, the following message appeared during boot-up: ‘Memory parity Error, System Halted’. For a while I ignored this message as letting the computer cool down would allow the computer to work. I recently discovered a virus on the computer. I installed PC-Cillin 2003 and used a set of emergency rescue disks to clean the virus. Now the memory parity error appears every time I turn on the computer. Could rescue disks be the cause of the error, or something else? The computer is an IBM Aptiva Pentium II with 192MB RAM running Windows 98.

As this problem only occurred after upgrading your RAM, it is most likely related to RAM. While there are some other possible causes of the problem, the fact that this happened so close to upgrading your RAM makes this the most probable cause. Possibilities include the incorrect type of RAM or different types of RAM have been mixed. Interestingly enough, reading Microsoft Knowledge Base reveals that this could also occur if you have non-proprietary RAM installed on a motherboard which requires proprietary RAM (this may be relevant since you have a brand named machine). It is quite surprising how often the wrong type of RAM is installed in computers - just the other week a friend of mine asked why his computer wasn’t working after a memory upgrade. In that instance the wrong speed RAM had been installed (despite the speed being clearly labelled on the RAM chip). My advice is to take your machine back to where it was upgraded to have the problem resolved.