Credit report - Misused information

Hi, i recently looked at my credit report and have found that i have vast amounts of searches by companies i have never used although someone has used my name but mispelt it and address i have never heard of.
After reporting this to experian they have asked me to contact the creditors directly but no one seems to know who to direct me to or i just get ignored.

Am i right in thinking the details they hold could have been effecting my credit rating? Am i right in asking them to revoke the information? Also, i previously lived with a male friend, neither of us applied for any form of credit yet companies have searches as joint applications at our address?
Anyone out there can help would be gratefully appreciated.

x K x