Billerica - Ms. Sandra (Sandy) J. Serval-Cormier, of Billerica, formerly of Wakefield and Waltham, died Friday October 5, 2007 in Lahey Clinic, Burlington, after a lengthy illness. She was 40. Sandra was born July 12, 1967 in Waltham, a daughter of the late Joseph M. and Zita M. (Murphy) Serval. She lived many years in Waltham until her parents deaths and later moved to Wakefield with her sister to be raised by her aunt, Eleanor Cass. She had lived in Billerica for many years. She was a graduate of Wakefield High School, Class of 1985. She then earned an associate degree in engineering from Middlesex Community College. Sandra had worked as an engineer specialist for over 8 years at Textron Defense Company in Wilmington. She was a longtime Rottweiller owner and loved spending time with her Rottweiler Dimitri. Her other dogs included Bafin, Devin and Haydin. Other interests and loves included decorating and fixing up her home, gardening and electronics. She leaves a sister, Caroline M. Abely and her husband, Allan E., of West Townsend; aunts and uncles, including, Josephine and Roy McDowell, Sr., Stanley and Alma Serval, all of Waltham, Eleanor Cass of Wakefield and Clyde and Charlene Murphy of Teaticket, many cousins, relatives and friends both locally and on Prince Edward Island in Canada. Special thanks to her close friends, Gail Cappadona, Lori Lodato and Karen Hayes for help with her dog during her illness. A special word of thanks is extended to Bob Lutz, both neighbor and good friend who provided invaluable assistance to Sandra during her illness. A Funeral Service for Sandra will be held on Saturday at 10:30 a.m. in The Joyce Funeral Home, 245 Main Street (Rte.20), Waltham. Burial will be in Calvary Cemetery, Waltham. Visiting hours will be held Friday from 4 to 8 p.m. In lieu of flowers, memorial donations in Sandras name may be made to NERR&R, Inc., PO Box 510, Portsmouth, RI 02871 (New England Rotweiler Rescue & Referral).