Re: connect phone

If it works with your relative's PC and not with yours, something is wrong with yours. The obvious candidates:
1. USB drivers
2. corrupted OS or malware
3. bad hardware

You didn't tell about #1, so I assume they are OK (meaning: your USB mouse, keyboard, printer, memory stick, scanner, external hard drive work).
That leaves #2 and #3. Now do a clean install of Windows XP (from the recovery media or partition), or from the XP and driver CD's and see if it works. If it still doesn't work, it's a hardware issue. If it works now, your problem is solved.