MTA crash to desktop on join game

[[DooD]Heavyair]

hello all

i have recently developed a problem with one of my copys of MTA

the system it is on is

celeron 2.4 / 768Mb RAM / ATI 9550 graphics (256Mb RAM) / 40Gb free on hard drive after install / Windows XP SP2

up until yesterday it was running fine but now crashes when i join game

all logo screens and splash screen are fine but when i connect to server the player spawns ( i can see him stood there ) resource download starts and gets to about 2-10 Kb left to download and 2 times finished resource download but then drops straight back to desktop with no error reported.

i have tried a reinstall of GTA SA and MTA DP2 then i tried updating graphics drivers and directx 9.0c but still does exactly the same thing. i am trying to join my own server on LAN and dont know what else to try. 2 other PCs on same network play fine on public or my own LAN server.

i ran into a similar problem with same PC a couple of months ago after installing AVG antivirus and ended up having to do full windows reinstall but this time the problem seems to have come from nowhere.

any ideas would be really appreciated as the next step will be XP reinstall but i really dont want to do that as i have a lot of other games on there and dont want to lose all my saves ( i can never figure out how to back them up properly )

thanx again