OK so a few weeks back I purchased a Belkin wireless mouse and keyboard. I researched them and was confident I'd got the best bang for the buck. For the first week they worked faultlessly, with my receiver on the floor just next to the base unit. I then had a technical guy come to fix some other problems with the PC(replace PSU, CPU fan and troubleshoot some other issues) and after he had done a few things he say's "This mouse is sluggish". I dunno if it's coincidence but since he came and worked on the PC both the mouse and keyboard haven't always worked properly. I'm starting to think it might be a BIOS issue cos he did change a few things in it for other reasons.
Since then I've done a fresh install of XP and replaced my graphics card and I now have to have the receiver right next to the mouse for it to work properly, and even then it sometimes acts up. Bizarrely, it sometimes stops responding completely if I change graphical resolution to a really high setting, and when I play FIFA 2005 the keyboard and mouse barely respond at all. I've tried uninstalling and reinstalling the drivers and having brand new batteries in both etc but to no avail. I also can't find any newer drivers. It seems strange it used to work fine with the receiver on the floor and now I have to have it right next to the mouse and keyboard.
I know the consensus will probably be to buy a wired mouse and keyboard but I don't have any spare cash at the moment(spent a lot on this PC recently) so that is out. Is this a problem in device manager or the bios maybe? Something is wrong because it used to work faultlessly. All help and suggestions will be much appreciated.