To cut a long story short i was doing a memory upgrade on my mothers PC while she was on holiday, i got some new RAM i installed it, everything looked fine in the BIOS and cpu-z so i let it run. 2 weeks later while running some anti spyware software and scanning the registry the PC crashed for the first time in 2 years, corrupting the registry in the process. The crash happened 2 days before she came home and she had about 1GB of holiday photos on the harddisk which had never been backed up, oops 
I managed to recover almost everything and then do a complete reinstall but i'm still not sure if it was the new RAM which caused the crash or if it was just fate and coincidence that nearly gave me a heartattack
So now i have 2 RAM modules, the only differences between them are memory size ( the old one is 128MB the new 256MB) and manufacturer ( the original RAM was from a comlete unknown), using CPU-z all other specs are the same.
I used memtest to check the RAM, when tested alone both modules showed 0 faults after about 8 passes.
Then i tested them together. On the first test i put the 256MB in slot 1 and 128MB in slot 2. This time i came up with errors on the 1st pass. tests 1,2,4,6,7 and 8 showed 0 errors. test 3 had 2 errors and test 5 got to 98% complete without an error and then came up with about 200,000 errors for the last 2% of the test.
Then i switched the modules around, 128MB in slot 1 and 256MB in slot 2. I got the same results except this time on test 5 i only got 2000 errors.
Are these errors caused by faulty RAM or is it just that the 2 sticks are incompatable and won't work together ?
Also should the PC run fine using just the 256MB of RAM alone as memtest showed 0 errors using just that stick ?
Its not my PC and i don't want to break anything more
so any help advice would be greatly appreciated.
To top it all off i ran the PC for over 100 hours using the original memory, 128MB PC2100 and a 512MB PC3200 RAM stick from my PC without a hitch, before i bought anything, everything about those 2 stick was different but they ran fine together so i assumed memory which met the exact specs would have no problems
I managed to recover almost everything and then do a complete reinstall but i'm still not sure if it was the new RAM which caused the crash or if it was just fate and coincidence that nearly gave me a heartattack
So now i have 2 RAM modules, the only differences between them are memory size ( the old one is 128MB the new 256MB) and manufacturer ( the original RAM was from a comlete unknown), using CPU-z all other specs are the same.
I used memtest to check the RAM, when tested alone both modules showed 0 faults after about 8 passes.
Then i tested them together. On the first test i put the 256MB in slot 1 and 128MB in slot 2. This time i came up with errors on the 1st pass. tests 1,2,4,6,7 and 8 showed 0 errors. test 3 had 2 errors and test 5 got to 98% complete without an error and then came up with about 200,000 errors for the last 2% of the test.
Then i switched the modules around, 128MB in slot 1 and 256MB in slot 2. I got the same results except this time on test 5 i only got 2000 errors.
Are these errors caused by faulty RAM or is it just that the 2 sticks are incompatable and won't work together ?
Also should the PC run fine using just the 256MB of RAM alone as memtest showed 0 errors using just that stick ?
Its not my PC and i don't want to break anything more
so any help advice would be greatly appreciated. To top it all off i ran the PC for over 100 hours using the original memory, 128MB PC2100 and a 512MB PC3200 RAM stick from my PC without a hitch, before i bought anything, everything about those 2 stick was different but they ran fine together so i assumed memory which met the exact specs would have no problems
