ShabbyA:
If your friend's "just touching the 'red wire'" did momentarily restore your connection; and if that same connection's has now gone flaky again (your "CABLE UNPLUGGED" message in the TaskBar/Tray), it's just possible that you DO need a replacement cable.
Do you know if the "red wire" is a standard "Ethernet" connection to the school's network? If so, then the cable is probably a CAT-5 (or -5e or -6) Ethernet patch cable. If ity's a patch cable, then the plug you insert into your DELL laptop (Inspiron? Latitude?) would be wider than a standard telephone jack, but would otherwise look very similar to a clear telephone connector.
If the school provides network cables for students to connect, you could just ask IT for a replacement "patch cable" (and of course explain the situation, as you did here). But even if the cable is yours (i.e., you brought it with you to school), a 14-foot Belkin CAT-5 patch cable at Staples is only $12 ($8 for a 7-ft) ( http://www.staples.com/ ); and Walmart has a 14-ft Belkin for $9 ( http://www.walmart.com/catalog/product.do?product_id=932040 ).
Of course if you brought your laptop to IT, they could determine with certainty whether your only problem is the cable.
Good luck!
Ken