is there a way to start a new account on a computer with an existing account? My rank is very low and I have over 2000 games played. Often host will kick me because of that combination.
Need New Account
No, creating multiple accounts is smurfing and will get you banned.
What you should do is play some 1v1 games. Your rating will adjust much quicker in 1v1 than in team games. If you are underrated you will easily win and your rating will increase.
Are you concerned that your rating is unfairly low, because you actually have good skills? If that's the problem, then do what @Askaholic said, play custom 1v1 matches to gain rating.
OR is the problem that your rating is accurate? If that's the situation, you need a different solution:
1 - git gud. You have to want to git gud, practice in 1v1s to get there (you won't learn anything in team games, you have 2k team games already, in order to learn you need to take responsibility for everything). I wrote a guide for 1v1s that can give you ideas of what to work on.
2 - host your own lobbies. Nobody can kick you, you can kick anybody, you can "foe" people to keep them away from your lobbies.
Take control. Take control of your rating or take control of the lobbies you play in.