Consider this scenario:

Please don't say that it would be better if I created a Domain network;
Just consider this scenario.

10 PCs are all interconnected via a switch to a workgroup network named WORKGROUP;

PCs specs(all are the same): Windows XP SP2 en (build:2600.xpsp_sp2_rtm.040803-2158)

I have full physical control over my own PC (one of those 10 PCs) and what I know about the other ones:

IPs of all 10 PCs.

Administrator account name of all 10 PCs.

Administrator account password of all 10 PCs.

How can I execute an application on the other PCs???(without touching them)

How can modify their registry settings???(without touching them)