Unless you know what nickname he uses, is pretty much impossible to find him. Suppose his nickname is rsmith, on DALnet you could type
/whois rsmith or
/nickserv info rsmith Commonly, ppl do not know a users real name and only know them by nickname. If you have a nick registered on DALnet you could try checking thru
http://users.dal.net/ on the off chance the person you are looking for has a profile there and perhaps listed puter repair as an interest, or for channels related to puter repair that he mite frequent. On DALnet you could try to get a channel list with
/list *repair* or
/list *some city or state here* Good luck