Below is a STSADM command which can help if you cannot stop or start a service within Central Administration. I haven’t had to use this often, but some people may find it of use. This example is based on the SharePoint Foundation Workflow Timer Service.
If you are not sure what service to firstly stop, you should run this command against the BIN location;
stsadm -o enumservices > C:\OUTPUT.txt
This will output all the services to an output file. Open this, and CTRL-F the relevant service in Central Admin. When found you will want to look for the ‘Type’ and ‘Name’ entries which match to the -servicetype and -servicename parts in the below STSADM command.
NOTE: Some have just ‘Type’ entries, when they do, JUST run the -servicetype part of the provisionservice command. If a ‘Name’ is stated, you will then need to ALSO specify the -servicename part like in the below example
stsadm -o provisionservice -action stop -servicetype SPWorkflowTimerService -servicename spworkflowtimerv4