The general rule is that if you have two subjects joined by or, the verb agrees with the proximate or nearest subject. Theoretically, therefore, you should say:
- If you or someone you know is having trouble logging on to VMware, please ask Bob Smith for help
However, it is possible to make or someone you know look or sound like a parenthetical insertion (eg say 'someone you know' in an undertone). In this case, I might want to get the verb to agree with the first subject:
- If you (or someone you know) are having trouble logging on to VMware, please ask Bob Smith for help
- If you - or someone you know - are having trouble logging on to VMware, please ask Bob Smith for help
All of this is of course potentially awkward, and the best solution might be just to avoid this altogether and recast your sentence! If anyone is having trouble ..., If you or any people you know are having trouble .... It isn't always cowardly to avoid an awkward construction.