Epson printer downs USB ports?

[Dog Doctor]

I have a Dell Dimension 2400 - standard edition but I have increased the RAM to 1GB. Operating system Windows XP Professional, ADSL broadband. Just changed my printer from Dell to Epson Stylus DX7450 and now find that if the printer is on, my USB ports don't work, i.e, webcam, flash drive, etc. With the printer off, they work fine. I have 4 USB ports at the back and 2 at the front of my PC and have tried switching devices. Also downloaded new print drivers. Took printer back to PC World and they changed it but the problem persists. Dell support spent almost 3 hours trying to resolve with remote access to my PC but failed. Microsoft say it is Dell's problem because my software was factory loaded. Epson say not their problem either if my operating system can't cope but could be IRQ numbering conflict. I'm a med student and really need to work off my flash drive but now am forced to work off my PC if I want to print or use webcam. Any ideas?

 

[itsme]

Took printer back to PC World and they changed it but the problem persists

If you talk nice to them ask them to replace with a Canon printer as the problem seems to be the drivers for Epson? as they could not resolve it with remote access, but are reluctant to admit driver problem?
Good luck get back if it works or not.
PS welcome.