One terrible hack-a-round would be try to upload using Linux in VirtualBox with the serial port linked.
If it is FUBAR'ed, then it will not hurt anything to install Linux. Linux usually uses much less RAM and CPU and will run faster on an old computer. Main disadvantage is there isn't as much software available. Fortunately, some windows software can be run in WINE. There is also a reasonable amount of open source software available. Package managers suck though (always FUBAR the system )