If basic troubleshooting procedures do not solve your problem, it might be best to call support sooner rather than later. In many cases when a novice has tried to fix an issue with their or their friends computer, what they have actually actually accomplished is to make the problem worse, which has then ended up costing much more money. When troubleshooting involves cleaning up windows registry, it is best left to the professionals, as one wrong keystroke or mouse click can render your Operating System useless, necessitating complete re-installation of the Operating System exponentially increasing repair costs.
The other factor to consider is, how long can you be without your computer? If getting a friend to try and troubleshoot your computer is going to take a day or two, and a professional can do it in one or two hours, it may well be worth your while to get the professional to start with so you can continue using your computer to generate income for your own business.