I have a hotmail account and everytime I send a mail an advertisment for 'meet sexy singles today @lavalife - click here' appears. Then a long link appears.
You need to download free protection such as Ad-aware and spywareblaster.
Do you have a pop up blocker.
I have a hotmail account and do not have these troubles.
Yeah - your machine is probably infected with malware of some sort. Anything from adware to a virus. You need to sort it out. See the "clean PC" key thread pinned at the top of this forum.