The small business ends up being a greay area, some of those models are the home pc's and some are the business pc's so you tend to get random support centers. If it was an inspiron for example even though it may show up in the small business menu it still gets the home support call center. Any other brand does the same thing.
Though your problems sounds more like a windows than a computer problem. If you really don't want to buy a new computer and don't want to format the drive thas in there spend $50 on a new drive and stick it in then reinstall. Then if its stable buy a $20 usb enclosure and stick your old drive in it then copy the data over. I do that myself and the old drive becomes the backup and after I'm back and running normally then it gets the data copied to it and goes in the gun safe.