USB problems seem to be a reoccurring theme so I thought I would share this.
About 4 months ago, I bought and installed a cheap ($15.00) "Rosewell, Model: RC-301, 2 port serial PCI card from NewEgg. Installation was simple, and it has been working perfectly 24 hrs a day, 7 days a week with three com ports in use at all times.
Although I installed it on an XP machine, They spec. it as being compatable with Vista as well, and a couple of the reviews seem to support that.
Might be worth a try for any brave soles out there.
Brand Rosewill Model RC-301 Spec Type PCI to Serial Port Card External Ports 2 x 9 pins serial connectors Data Transfer Rate 1 Mbytes/sec Operating Systems Supported Win95/98/NT4.0/2k/XP/XP64/DOS/Vista 32/64bit / Linux Specifications Chipset: MOSCHIP MCS9835CV Features Features Supports up to 2x 16550 Fast Uart serial port
Easy Plug and Play installation
Automatically selects IRQ & IO address
Supports IRQ sharing
Built in 16C550 compatible UART with 16byte transmit-receive FIFO
Multi card capability allow for upgrade with additional serial or parallel cards
For 5V PCI slot only
Package Contents Manual, CD Drivers,RC-301 Serial Port Card
Hope it Helps,