You cannot merge the partitions without a program such as Partition Magic or Acronis Disk Director
There are free ware and share ware programs that do similar things
If you are not worried about loosing data and don't wish to buy a program then simply backup anything critical and start again.
Make certain you have all the drivers and licence numbers first.
If you know somw-one with Partition Magic, they may be prepared to install your hard disk as a slave in their machine and do this for you.
Be prepared for them to need to virus scan your hard disk first.